Automatic trunking system.



,No. 878,265. PATENTBD FEB. 4, 1908.

G. S. WINSTON. AUTOMATIC TRUNKING SYSTEM.

APPLICATION FILED JAN. 2, 1907.

I a citizen of the United States, residing CHARLES S. WINSTON, OF CHICAGO, ILLINOI S, AS SIGNORTO KELLOGG SWITOHBOARDL 'AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TRUN KIN G SYS'IEM.

Specification of Letters Patent.

Patented Feb. 4, 1908.

Applioation filed J'zsuuniry 2. 1907. Serial No. 360.336-

To all whom it may concern: 7

Be it known that I, CHARLES S. WINsTo v, in

Chicago, county of Cook, and State of Illi- -nois, have invented certain new and useful Improvements in Automatic Trunking Systems, of which the following is a specification. My invention relates to telephonic circuits adapted to be used in completing connections etween automaticand manual exchanges, and between manual and automatic exchanges, whereby the subscribers of the automatic and manual exchanges will be mutually enabled to connect arid talk, one with the other.

The object of my invention is to simplify the circuits and apparatus for such connections, endin connection therewith to an range means for disconnecting or restoring the apparatus of the" automatic exchange Without additional effort'on the part of the manual trunk operator, and. at the same time to make such an arrangement that the trunk I connecting plug can be changed from one as jack to another without disconnecting or restoring theapparatus of the automatic ex1 in'limbs 4 and 5 '3, 3 3 and 3 may change.

My invention is illustrated in the accomanying drawing-which shows the two reays 1 and 2 at the automatic exchange connected with the trunk line 3, which extends I to the manual exchange, where it terminates in a cord circuitadapted to be directly ers" lines of the manual exchange. The automatic exchange itself is to be understood to be conventionally shown and other trunks,

also 7 be similarly provided. It is to be understood that the-portion of this cord circuit to the right of the condensers may be of any'form to correspond or to actuate in connection with the lines of the exchange, which maybe of any forn'i, the;

line .6, here shown, being of theoonnnon battery type terminating in the cut-off jack 7, and having the line relay particular op- I ratcrs position, r which airzmgcment one calling device is sullicicnt for any number of 1 trunks.

connected with the subscrib S normally con.

provided with the calling device 10, which is arranged through keys 11, 12, 13, etc, to beconnected'with all of the trunks associated with a here shown in the position which it assumes when the plug is seated therein. Conductors 21 and 22 extend from the conductors 14 and 15, upon the end of thetrunk which connects to the automatic exchange, to the springs 23 and 24 of, the relay 19, these springs being normally in connection respectively with contacts 25 and 26, which connect with the two/terminals of the drop 27, and also with the normally open contacts 28 and 29 of the slow acting relay 30. Contact 25 of relay 19 is also connected with the coil of relay 31 the other terminal of this coil being connected through conductor 32 with the normally .open contacts 33 and 34 of relay 30, the latter contact being connected with ground through the conductor 35.

Relay 31 controls the normally closed contacts 36 ai1d 37 contact 36 being connected with ground conductor 38, and contact 37 being connected with the normally open contact 39 o'f'relay 30. The spring 40 of relay 30.1's connected with the, coil'of such relay, and also with the normally open contacts 41 and 42 of relay 19., contact .42 being con' nected with relay 30 is connected by conductor 43 with. live pole of battery. Thisrelay is provided with the copper shell 45 in order to make itretain its "ma netism after the current has been severed .rom its coil, and therefore to ground. The other terminal of cause its contacts to be held in their abnormal position for a short period after the current throiwh the coil has been interrupted.

The corr circuit as here shown is provided on the right of the condensers with the relay 46 having. two coils, one connected between the 'live pole of battery and the talking strand 15,'and the other between the ground pole of battery and'the talking strand .14. lay'serves to control the contact springs 47 and. 48 which are normally in the closed circuit of the supervisory signal 49, the circuit of this signal being completed when a-connection is made with a subscribers line through the conductor 50 andthe sleeve con.- tact of the plug and jack. The usual ringing key 51 is provided withfseries-contacts such that ringing current may be connected with line re'' 56 and battery 57.

the called lineonly, and the listening key is connected in the usual way with the conductors .14 and '15 such that theoperators set may be bridged'across thetalkingcircuit.

' This operators set consists of the condenser 53', repeating coil 54, receiver 55, and the In the operation of the system, supposing primary the first call to originate in the-automatic ex change, the calling subscriber will be automatically connected with the lines 4 and 5 of thejtrunk 3, this trunk being given a number in the automatic exchange, such that it may 'beconnected with by the operationof'the mechanism at-any substation of the auto-v *m'atic s stem.

After the connection is thus establis ed signaling current will be sent upon the trunk line the-same as it would be uponany subscribers line of the automatic indicate to the trunk 0 tionhas been made wit system. This signaling current will pass over conductors 4, 14 and 21 throughthe normal contacts 23 and 25 of relay19, and

through the coil of the .drop 27, normal con tacts 26 and 24 of relay 19, conductors 22,15

and 5 back to the source at the-automatic exchange. This will throw. thedrop 27 and tom-atic exchange. The trunk o erator now throws her listening key 52 and nquires the desired number of the automatic subscriber.

Thejoperator may in the meantime lift her plug 16 from the plug-seat-switch 20 and close the circuit of relay 19, but herfailure to do this'will not affect the conversational condition of the trunk for the reason that the drop 27 is given sufiicient importance not .to materially interfere with-the conversationif it is allowed to remain bridgedacross the line.

'When the trunkoperator lifts her plug 16 from the plug-sea't-switch 20 the circuit of the relay 19 is closed from the live pole of battery B to ground through the plu -seatswitch. This actuates thes rings o relay 19, opening the contacts 23 an 25, and 24 andv 26*,and closing the contacts 41 and 42. Theselatter contacts close the circuit of relay 30 connects round wit from battery B through conductor 43, the coil of the relay-and contacts 41 and 42 to ground. Relay 30 isthereby actuated and its springs move-to close the contacts 33 and 34,- 28 and 29, and 39-and 40; .The 28 and 29 places a shunt about t e coil of the drop 27. The closin of contacts 33 and34 one terminal of the relay 31, the other terminal being-now open at contacts 23 and 25, 24 and 26. The closing of contacts 39 and 40 closes a locking circuit for relay 30 through the normal contacts I relay nerator thata connec-- the trunk at the au ays 1 and 2 in the automatic exchange to 'coil has been severed, maintain the ground connection upon the closin 'ofcontacts 36 and 37 of relay 31 such that relay 1'9jmay now fall back without opening the circuit of 30., Tl'ie trunk operator nowinserts her plug 16 and calls the desired subscribers line by throwing her ringing1 key 51. insertion of this plug closes t e circuit of the signal-49, contacts 48-and 47' of relay 46, oonductor 50'and the -sleeve contacts of the plug and jack to ground. Whenthe subscriber answers, relay-46 is actuated and contacts47 and 48 are separated to sever the circuit of the signal 49. When the conversation is- The supervisory lamp 49 from battery B through completed and the signal 49 is again displayed by the called subscriber hanging up 's receiver the plug is removed from jack 7 and allowed to assume its normal position in the plug-seat-switch 20, and thus to break the circuit of relay 19. The springs of this relay falling back close a circuit between conductors 14 and 15 through contacts 23 and 25, and,24 and 26, respectively, the closed. contacts-28 and 29 of relay 30, in the latter instance, andthrough the coil of relay 31', conductor 32, contacts 33 and 34, and conductor 35 to ground. Thus, a ground connection is placed uponeach of the limbs of the trunk l ne and current flows from battery B through the coils of relays 1 and 2 in the automatic exchange over both limbs of and contacts 33 and 34 otrelay 30 to round. Current in this path'actu'ates rerestore the nechanism and alsoactuates relay 31 and thereby opens the locking circuit. of relay 30 at thc contacts 36 and 37. Relay 30, thus having its'circuit severed, will fall back and sever the round connection with the limbs of the trun at contacts 33 and 3 4,

but this relay 30 being provided with the copper shell 45 will not actuate for an appreciable length of time after the circuit of its and therefore will limbs of the trunk an ample time for the restoring mechanism .at the automatic ex? changeflohave completely operated. This trunk circuit being a'dapted for reciprocal operation the call may arise at the manual the trunk line, throughv the coil of relay 31,

exchange, in whichcase'the line signal 9 will be displayed in the usual way, and the -operator will insert her plug 16 and inquire the number of the. desired Having determinedthe operator throws her key 11 and operates'the dial of the calling device 10 in the same man- .ner as would an ordinary subscriberof the and. thereby places the automatic exchange, trunk'line in connection with the desired subscriber. The button 531s then pressed and the automatic subscriber manner provided in the automatic subscriber. 1

desired number the,

is signaled in the j automatic exchange.

The connection any being complete the dis-" connect is accomplished in the same manner could be made to operate at as though the call arosein the automatic ex change.

It will be seen that by the use of the plugseat-switch, whereby therestoring circuit s not closed untilthe lug is released from the trunk operators end Operator make an error in connecting with the line desired by the automatic subscriber that the plu' may be removed from the jacks and inserte( into another jack without restoring the automatic mechanism. The relay 19 the time the plug 16 is inserted in a jack, but this would e objectionable for the reason above stated.

It is to be understood'that batteries B, B and B may be, and in practice are, one, and that B may be this same battery, but in practice is usually separate and located at an exchange some distance from the manual exchange.

While'manyfeatures of this system have been here described in detail, it is to be understood that I .do not wish to be unduly lmited thereto, it being very possible to use certain features of this invention with other forms 'ofautomatic exchanges than the one here shown, and with automatic exchanges which require a different connection for restoring than does this one without departing from the spirit or scope of this invention.

What I claim as new and desire to secure by Letters Patent is:

1. In a telephone system, the combination with automatic and manual subscribers lines terminating in their respective offices, of a trunk circuit for connecting the lines of the two systems for conversation extending between the ,oliices andterminating at the manual exchanga in a'cord and plug, and means to maintain a ground connection on both limbs of the telephone line for a short duration of time when-the conversation has been terminated, substantially as described.

2. In a telephone system, the combination with automatic and manual subscribers lines terminating in their respective offices, of a trunk circuit for connecting the lines of the two systems for conversation extending between the offices and terminating in the manual exchange in a cord and plug, and means to make and maintain a restoring connection with the trunk line for a short dura-v tion of time when the conversation has been terminated, substantially as described.

that should the trunk 'natcd,the control of such the removal of the plug from the manual subofa trunk circuit for connecting the lines of the two systems'for conversation extending between the offices and terminating in the manual exchange in a cord and plug, and

'means for maintaining a connection with the trunk when the conversation has been termimeans permitting scriberss line without the actuation of such means, substantially as described.

'4. In a telephone system, the combina-" tion ith automatic and manual subscribers lines, of a trunk circuit for connecting such lines for conversation, a plug and a terminal for one end of said trunk line, a seat switch for-fsaid plug, and means operated by the actuation of said plug-seat-switch for maintaining a connection with. the trunk line for a short duration of time after described.

5I In a telephone system, the combination with automatic and manual subscribers lines, of a trunk circuit for connecting such lines for conversation, a plug and a terminal for one end of said trunk line, a seat switch for said plug, and means for maintaining a ground connection on both limbs of the trunk line for a short duration of time after the plugseat-switch has been act'u'ated, substantially as dcscribed. I

6. In a telephone system, the combination with automatic and manual subscribers lines terminating at their respective switchboards, of a trunk circuit for connecting the lines of the two systems for conversation terminatin at the manual switchboard in a cord and pIug, and means at the manual exchange for altering the circuit of the trunk when the conversation has been terminated, whereby the automatic switching mechanism at the automatic exchange is restored to its normal condition, substantially as described.

county of Cook,

and State of Illinois, in the witnesses.

CHARLES S. WINSTON. Witnesses:

, CLIFFORD CJBRAD'BURY,

EDITH F. Gama.

the plug-seat switch has been actuated, substantially as Cbrrecti'on in Letters Patent- N0. 878,265.

"11; is' hereby crtified that in Letfi ers Patent No. 878,265, granted February 1908,-

' upon the applicatioli of Charles S. Wins ton, of Chicago, Illinois, for'an improvementv in Autdma.ta i'c Trunking System s, an error amxgamxsinv theprinted specification requiring correction, as follows: I n 1i ne'42, page 2, the word im o should read impdan'ce; and that t h .aid Letters 'Patent shouldbe read with this correction ther gih' the mt" the same may cdnforni 1:0 the record of the case in the Patent Office.

Signed and healed this 3rd day of March, 'A. I 1908.

[my 0. c. BILLINGS,

Acting Commissioner 0f Patents. 

